• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1358-1360
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• 1998

In this paper, organic thin film LED(light emitting diode) having ITO glass/$Alq_3$/Al structure using an $Alq_3$ was fabricated by the vacuum evaporation and the absorbance, wave length, 1-V characteristics were investigated. Electroluminescence of green and wavelength of 510[nm] were observed in this device. We observed absorbance form 320[nm] to 430[nm] and knew unstability of $Alq_3$ material as light emitting device.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.154-157
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• 2000

One of the problems using DCR(Direct Conversion Receiver) type architecture are DC offset, Poor channel selectivity. APDP(Anti Parallel Diode Pair) can be mood candidate for the DCR frequency mixer due to its inherent 2nd harmonic suppression. APDP shows good IP2 and DC suppression. This paper describes single APDP LO power characteristics, IP2, and receiver structure utilizing APDP frequency mixer.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.9
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• pp.1369-1374
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• 1989

Electrical characteristics at the p-GaP semiconductor/CsNO3 electrolyte interfaces were investigated. It is found that such interfacial phenomena are well analyzed by semiconductor-semiconductor pn junction diode models and image charge effects of semiconductor-vacuum interfaces. The formation processes of electrical double layers and their potential variations are verified using cyclic voltammetric methods. The interfacial current are influenced by Cs+ ion coverage onto the semiconductor electrode surface and structure of electrical double layer.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.7
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• pp.71-78
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• 1997

In this paper, we analyzed the crosstalk characteristics of LD array modules for WDM and improved the crosstalk levels using a screening line between access lines. From the calculation resutls, we have found that inductive crosstalk of access lines is dominant for the low impedance LD arrays with short bondwire interconnections. The proposed array interconnecton with the screening line and ouble bondwires, rduces the crosstalk level about 10dB compared to conventional interconnections using simple access lines and a single bondwire. This proposed structure also can be easily imlemented with transmission reliability.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.169-173
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• 2003

In this paper, we present a design and experiment study of high power large diameter backward wave oscillator. Analysis is made within the scope of linear theory of absolute instibility. The Electron beam generator may be atteractive source of high power millimeter microwaves which has simpler structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.439-442
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• 1998

In this paper, organic thin film LED(light emitting diode) having ITO glass/Alq$_3$/Al structure using an Alq$_3$ was fabricated by the vacuum evaporation and the absorbance, wave length, I-V characteristics were investigated, Electroluminescence of green and wavelength of 510[nm] were observed in this device. We observed absorbance form 320[nm] to 430[nm] and knew unstability of Alq$_3$ material as light emitting device.

• Electrical & Electronic Materials
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• v.1 no.2
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• pp.109-114
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• 1988

AlGaAs/GaAs 이종접합구조 레이저 다이오드의 활성층 두께를 변화시킬때 스트라이프폭과 광출력에 미치는 영향을 해석하였다. 안정된 단일발진 도파모우드를 위해서는 R>O되어야 함을 밝혔다. 고출력에서 캐리어분포와 이득분포에 대해 공간적 호울버닝 현상이 일어났고 이는 출력을 고정시키고 스트라이프폭만을 찬넬폭보다 크게 하여도 발생하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4A
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• pp.219-226
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• 2012

We investigated the performance of a visible light communication (VLC) transceiver applicable to both of illumination and wireless communication. we considered the visibility of VLC, the easy connection for wireless communication and high-speed transmission and implemented VLC transceiver based on edge-emitting laser diode and silicon photodiode. The proposed VLC transceiver is designated to operate in a full duplex mode at high speed of 120 Mbit/s. The shielding method that is employed as a means to reduce the light cross coupling effect inside the VLC transceiver is proposed and its performance is experimentally measured. We also applied optical antenna to have the larger angle of field of view (FOV) to novel structure of VLC transceiver and examined and analyzed their bit error rate performance, photometric result with respect to the transmission distance, the coverage range and the tilt degree as transmission link characteristic between two transceivers without optical antenna and with optical antenna.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.533-538
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• 2001

The ZnSe sample grown by chemical bath deposition (CBD) method were annealed in Ar gas at 450$^{\circ}C$ Using extrapolation method of X-ray diffraction pattern, it was found to have zinc blend structure whose lattice parameter a$\_$o/ was 5.6687 ${\AA}$. From Hall effect, the mobility was likely to be decreased by impurity scattering at temperature range from 10 K to 150 K and by lattice scattering at temperature range from 150 K to 29 3K. The band gap given by the transmission edge changed from 2.7005 eV at 293 K to 2.8739 eV at 10 K. Comparing photocurrent peak position with transmission edge, we could find that photocurrent peaks due to excition electrons from valence band, $\Gamma$$\_$8/ and $\Gamma$$\_$7/ to conduction band $\Gamma$$\_$6/ were observed at photocurrent spectrum. From the photocurrent spectra by illumination of polarized light on the ZnSe thin film, we have found that values of spin orbit coupling splitting Δso is 0.0981 eV. From the PL spectra at 10 K, the peaks corresponding to free bound excitons and D-A pair and a broad emission band due to SA is identified. The binding energy of the free excitons are determined to be 0.0612 eV and the dissipation energy of the donor -bound exciton and acceptor-bound exciton to be 0.0172 eV, 0.0310 eV, respectively.

• Korean Journal of Materials Research
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• v.18 no.7
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• pp.379-383
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• 2008

We report on the light-emitting diode (LED) characteristics of core-shell CdSe/ZnS nanocrystal quantum dots (QDs) embedded in $TiO_2$thin films on a Si substrate. A simple p-n junction could be formed when nanocrystal QDs on a p-type Si substrate were embedded in ${\sim}5\;nm$ thick $TiO_2$ thin film, which is inherently an n-type semiconductor. The $TiO_2$ thin film was deposited over QDs at $200^{\circ}C$ using plasma-enhanced metallorganic chemical vapor deposition. The LED structure of $TiO_2$/QDs/Si showed typical p-n diode currentvoltage and electroluminescence characteristics. The colloidal core-shell CdSe/ZnS QDs were synthesized via pyrolysis in the range of $220-280^{\circ}C$. Pyrolysis conditions were optimized through systematic studies as functions of synthesis temperature, reaction time, and surfactant amount.